Electric furnace.



PATENTED MAR. 12, 1907.

B. VON 'IsuHEmKY. ELECTRIC FURNAGE.-

APPLICATION FILED FEB. 15, 1906.

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WITNESSES 7% @k 3's transmit tlie'heat by radiation to the charge.

of current t UNITED STATES.

PATENT ()EFFIGE.

BASILIUS VON ISCHEWSKY, or KIEW, RUSSIA.-

ELECTRIC FURNACE.-

Specification of Letters Patent.., Patented hiarch 12, 190? Applicatiozi filed ebruary 15, 1908, Serial No. 301,122..

To (slit/172.0111, it may concern.-

Be' it known that I, BAsILIUs VON lscHEw-' SKY, a subject of the Emperor of Russia, re-

' siding at-Kiew', in the Empire of Russia, have metallurgic purposespresent the character invented a' new and useful Electric Furnace,

of which the following is a specification.

The hitherto-known. electric furnaces for istic feature. that the requiredelectric 'cur-.

rent has a very low pressure and a very large strength. Such a current may be supplied direct, as is the case with Hroults fur- -;property of'the hitherto known electric furtricitv to metallurgic purposes was rendered;

naces'has prevented their exploitation on a large scale, so that the application of the elecdifii'cult.

My invention relatesto an electric furnace;

which issuitable for all kinds of currents and presents the special advanta e that it permits the'use of currents of big pressure in a most. favorable manner.-

This. electric furnace is lined'with electric conductorsjof the;

second ,cla'ssthat is to say, such. materials which become conduct1ve only. at a. higher temperature-end, further,- this furnace is pro'vided'with a plurality of electrodes. which;

disposed as to form J ablochkofl? s can- SIB S0 dies and cause an intensive heating ofthe internal layer of the furnacewall, and thereby At the same time the current can be con''- ducted-'-, tlirough the metal of'-thecharge,

' which is;v often desirable-for-the production of certainfreactionsr iThere are know n' furnaces, it is true, which are not intended for working metals and" are lined with electric conductors of the second class; but the latter cannot produce the effect of Jablochkoffis candles. There are, moreover,- known furnaces the walls of which are turned into ordinary electric conductors by the addition of a conductive material, (such as graphite but such'furnaces require the employment of currentspf low ressure, and for alarge strength l feyjdo'not prove valuable, since the graphite'causes a rapidwaste ofthe fur:

nace-walls, so that their necessarily impaired.

The construction and the wall of my elecconducting power is trio-furnace are almost the same as those of the'usual Bessemer or Thomas .converter or Martin furnace, and an electric current of a high ,pressure is employed and is conducted through the wall, it bein preferably introduced into the furnace at t e vault or ceiling.

The-wall ismade of oxids, preferablymag-- nesia, calciu'mfoxid, and'pther oxids, eitherbasic or acid oxidsfthe same as in" Martin furnaces, or mixtures of the said materials may be em loyed, the essential point being that they s ould have sufficient conducting-- power and resistance at a corresponding temperature. The electrodes ,particularly those of carbon, are embedded"in the wall of the furnace in such'a manner that they adjoin the internal layer -of the furnace w'all.

In the accompanying drawing, in which the same parts aredenoted by the same reference, characters throughout;, the several views, Figure 1is a'vertical longitudinal seetion through anelectric furnace' constructed in accordance with the invention. Fig. 2'. is

a vertical transverse section,.and Fig. "3 is a torfi'plan v1ew.

eferrmg to the drawing, 1 denotes-the.

furnace proper, which is constructed in tlie] I 3 form. ot a horizontally-mounted hollow cylin-v der having an interior s ace-1 in'which the massto' bemelted, whic 1s denotedby reference-numeral'fz, is placed.

arranged in a verticalplane in a series eX- tending completely about the cylindrical furnace-wall and pass inwardly through the furnace wall and abut at 1 their inner ends against the inner layer 1)? of the latter. This wall is formed; by a pluralityof radial bricks f4, and the electrodes are disposed radiallybetween said-bricks, asrshown'. By this ar-' ran ement of the electrodes, thebricks of the f wal andthe interior layer 1?- the latter may 3 denotes thecarbon electrodes,which are I be heated to-in'candes'cence in; the natlire of Jablochkoifcandles, said layer being formed of a'material whichis a conductorv of the second classthat'is.to-say, a materialwhich' becomes electrically conductive only "at a high temperature.

The. electrodes 3 are se-jcured in the furnace-wall in such a manner as to permit their being pushed inwardly as they are burned away, and saidelectrodes'are connected together by lateral, pieces 5 as shown in Fig. 2. Said pieces 5 are m turn connected to conductors 6, as shown in Figs.

2 and. 3, and said conductors are in electrical i re communication with a commutator 7, against which bear two brushes 8 and 9, through which the current is supplied.

In order that the rotation of the furnace in- "the vertical plane in which the electrodes are located may be effected, the same is provided with longitudinal peripheral rails 10, which. rest on rollers 12, mounted on a suitable base 11. The furnace is illustrated as beingprovided with a crank 13, by which the same may be manually rotated; but it is apparent that in large and heavy furnaces rotary motion can be imparted by gearwheels or other suitable means.

To start the furnace, hot slag or other hot -material is introduced into the same and the furnace then turned somewhat, so that the inner layer of the Wall is heated up to such an extent as to become electrically conductive. When the current is switched in, it is conducted from one electrode, over the interior layer of the furnacewall, to the next electrode, and

' so on, so that the furnace-wall is heated up and produces by radiation the melting of the metal. By the arrangement of the electrodes in contact with the inner layer of the furnace-wall said layer quicklybecomes The course y the arrows' on heated to the required de rec. of the current is denoted Fig. 1 of the drawing. The current will pass from the internal layer 1 through the metal, and thereby product chemical reactions. If necessary, the direction of the current may be reversed or an alternating or multiphase current may be used instead of a direct cur-- rent. In the case of arotatory current at least three electrodes must be employed and they must have the same cross-section. In general, however, and when circumstances permit it, a greater number of electrodes is preferably provided, asshown, so as to form a sort. of J ablockhoffs candles, which heat merely the internal layer of the furnace-wall.

In the case of currents of low pressure it may be advisable to employ as many electrodes as possible, they being ofthe same cross-section. The number and arrangement of the electrodes must be such that no short-circuiting can take place between two electrodes through the metal bath. Under all circum stances it is necessary that at least one electrode be outside the bath, so. that the current shall be compelled to pass along the lining of the furnace.

As already mentioned, the current passing from the internal layer 1 through the metal of the charge will produce reactions between the added materials, the furnace-Walls and the fluxes of other bodies, so that the current may be utilized for refining the metalxor for carrying out other known methods, such as removing the carbon, silicon, phosphorus, &c.

The most important applications of the new electric furnace are as follows:

se'nooe' First. For Martin furnaces, (or course the usual generators and heat-accumulators may be dispensed with or they may merely serve -for the preliminary heating.) The carbon of the pig-iron or cast-iron should in this case go into calcium carbid and combinations of the iron. In some cases also suitable admixtures may be used for fining purposes.

Second For Bessemer or Thomas converters, if the pig-iron or cast-iron is too poor in heat-generating substances, such as silicon or phosphorus.

Third. For the production of crucible steel.

Fourth. For the production of copper and nickel by the Bessemer process in case the ores are rich in metal, also for working metals difficult to melt.

Fifth. For reheating metals which have cooled down during their working-for example, in rolls or beneath the steani-hamnier. Sixth. For heating deep furnaces, and, seventh, for melting, the materials which have been storedupon the hearth or in the boshos of a blast-furnace for want of coke or from other reasons.

The essential advantages of the new electric furnace are as follows: First, it has no carbon electrodes in contact with the charge, which is of special importance for processes of removing the carbon; second, when using consecutively electric furnaces with basic and acid linings all the added material can be removed; third, when employing liquid metals out of the blast-furnace (Pilz furnace) the electric furnace will work more economically than the Martin furnace or even the crucible furnace; fourth, the electric furnace permits the refining of such kinds of pig-iron 0r cast-iron as are quite poor in silicon or phosphorus, and it is useful for working the richest copper mattes by means of the Besseiner process; fifth, it renders impossible the formation of air-bubbles and other defects in cast-steel sixth, its output is by far larger than that of the Martin furnace, and,

seventh, the temperature can be easily ad justed at any time.

What I claim as my invention, and desire to secure by Letters Patent, is

An electric furnace comprising a hollow cylindrical body having a lining of material which is electrically conductivev only at a high temperature, and a plurality of electrodes housed in the cylindrical wall of said body and abutting at their inner ends against said lining.

In testimony whereof I have signed. my name to this specification in the presence of two subscribing witnesses.

BASILIUS VON lSCHElVbKY.

Witnesses v GUSTAVE HARTWIG, BASILIUS I insnnnrr. 

